1. Field of the Disclosure
The present disclosure relates to the field of laparoscopic surgical instruments. More particularly, the present disclosure relates to laparoscopic surgical instruments having an articulatable tool end.
2. Background Information
There has been a trend to perform surgery in the most minimally-invasive way. To this end, laparoscopic surgical instruments generally include a tube having an articulable distal end for performing a medical or surgical procedure to be performed, have been widely used because the incision necessary for insertion of such a tool on a medical device is typically small in comparison to alternative methods. As a result of the relatively smaller incision in comparison to open surgery, patients typically exhibit more rapid healing times and often experience fewer complications as a result of surgeries using such medical devices. Related art articulable surgical instruments are designed to mimic a surgeon's natural hand and/or finger motion in order to provide the surgeon with a safer, more natural-feeling mechanism by providing more natural feedback to the surgeon.
Such related art surgical instruments tend to have insertion portions (e.g., the lumen, stem or tube) having an outer diameter of 10 millimeters (mm) or greater, due to the amount of complicated mechanisms inside the instrument. While such articulated surgical instruments are laparoscopic in nature due the small incision in comparison to open surgery, there is a trend to make such laparoscopic incisions even smaller and in a lesser amount, thereby even further reducing the risk of complications from surgery, for example, by providing insertion portions having an outer diameter of 5 mm or less. When providing such a small surgical instrument, the internal components must be correspondingly reduced in number and size, but still must be robust enough to reliably perform the surgical procedure.
FIG. 9 shows schematic cross-sectional view of a related art surgical instrument 910. The instrument has a hollow lumen 912 affixed to an end segment 914 pivotably connected too the lumen by a joint 918, also referred to as a knuckle. Threaded within the lumen 912 and end segment 914 is an actuation cable 922. One end of the actuation cable 922 is affixed to a distal portion of the end segment 914, and another end of the actuation cable is affixed to a trigger (not shown). Actuation of the trigger creates tension in the articulation cable 922, the force of which pivots the end segment 914 at the knuckle 918 relative to the lumen 912. When the end segment 914 and lumen 912 are bent to a 90 degree angle (as shown), the cable 922 exits the confines of the instrument 910, subjecting it to damage and possible failure, thereby risking injury to the patient. Further, when the end segment 914 and lumen 912 are bent to such a 90 degree angle, the cable 922 drags over sharp edges 914E, 912E respectively formed at the ends of the end segment 914 and lumen 912, thereby subjecting the cable to fraying and possible failure, thereby risking injury to the patient.
Other related art surgical instruments propose using polymers at the knuckle region; however, such polymers have a very limited service life. Still other related art robotic surgical instruments use a micro sheave with a ball or roller bearing; however, such a configuration is costly and, due the precise nature of the bearings and high load on the cables, such instruments are reusable only a limited number of times (e.g., ten times).
In view of the above, a need has arisen for an articulable surgical instrument having a small outer diameter, yet having a reliable and safe articulation mechanism.